Efficacy, immunogenicity, and safety of a monovalent mRNA vaccine, ABO1020, in adults: A randomized, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: ABO1020 is a monovalent COVID-19 mRNA vaccine. Results from a phase 1 trial showed ABO1020 was safe and well tolerated, and phase 3 trials to evaluate the efficacy, immunogenicity, and safety of ABO1020 in healthy adults are urgently needed. METHODS: We conducted a multinational, randomized, placebo-controlled, double-blind, phase 3 trial among healthy adults (ClinicalTrials.gov: NCT05636319). Participants were randomly assigned (1:1) to receive either 2 doses of ABO1020 (15 µg per dose) or placebo, administered 28 days apart. The primary endpoint was the vaccine efficacy in preventing symptomatic COVID-19 cases that occurred at least 14 days post-full vaccination. The second endpoint included the neutralizing antibody titers against Omicron BA.5 and XBB and safety assessments. FINDINGS: A total of 14,138 participants were randomly assigned to receive either vaccine or placebo (7,069 participants in each group). A total of 366 symptomatic COVID-19 cases were confirmed 14 days after the second dose among 93 participants in the ABO1020 group and 273 participants in the placebo group, yielding a vaccine efficacy of 66.18% (95% confidence interval: 57.21-73.27, p < 0.0001). A single dose or two doses of ABO1020 elicited potent neutralizing antibodies against both BA.5 and XBB.1.5. The safety profile of ABO1020 was characterized by transient, mild-to-moderate fever, pain at the injection site, and headache. CONCLUSION: ABO1020 was well tolerated and conferred 66.18% protection against symptomatic COVID-19 in adults. FUNDING: National Key Research and Development Project of China, Innovation Fund for Medical Sciences from the CAMS, National Natural Science Foundation of China.

Natural carriage of Streptococcus pneumoniae is associated with increased experimental pneumococcal carriage but reduced conjugate vaccine efficacy in a human challenge model.

BACKGROUND: In Malawi, the national pneumococcal conjugate vaccine (PCV13) demonstrated less herd immunity than the USA, likely due to higher natural pneumococcal carriage rates. We assessed PCV13 efficacy against experimental pneumococcal carriage in healthy Malawian adults. We explored how natural carriage (pneumococcal carriage of any other serotype apart from 6B) influenced experimental carriage rates and vaccine efficacy. METHODS: Healthy adults aged 18-40 were randomly assigned PCV13 (n=98) or saline (n=106), followed by intranasal SPN 6B inoculation at 20,000 (n=40), 80,000 (n=74), or 160,000 (n=90) CFU/100µl, 28 days post-vaccination. We evaluated natural and experimental pneumococcal carriage before and after vaccination on days 2, 7, and 14 post-inoculation using culture and multiplex qPCR targeting lytA/cpsA genes and compared carriage rates by vaccination status. RESULTS: Of 204 participants, 19.6% (40) exhibited experimental carriage, detected by culture and 25.5% (52) by qPCR. Vaccinated individuals had lower experimental carriage rates (10.2%, n=10/98) compared to the placebo group (28.3%, n=30/106). This difference in vaccine efficacy was more pronounced in participants without natural carriage (PCV13=8% n=6/75 vs. placebo=25.9%, n=21/81) compared to those with natural carriage (PCV13=14.8%, n=4/27 vs. placebo=26.5%, n=9/34). Using a log-binomial model, vaccine effectiveness (VE) was 62%, whether assessed by culture or qPCR. Natural carriers had a lower VE of 52% compared to participants with no natural carriage (VE=69%). CONCLUSION: We have shown that PCV13 VE estimate (62%) is robust whether carriage is assessed by culture or qPCR. PCV13 had lower VE in natural carriers compared to those without natural carriage at the inoculation visit.

A mark-specific quantile regression model.

Quantile regression has become a widely used tool for analysing competing risk data. However, quantile regression for competing risk data with a continuous mark is still scarce. The mark variable is an extension of cause of failure in a classical competing risk model where cause of failure is replaced by a continuous mark only observed at uncensored failure times. An example of the continuous mark variable is the genetic distance that measures dissimilarity between the infecting virus and the virus contained in the vaccine construct. In this article, we propose a novel mark-specific quantile regression model. The proposed estimation method borrows strength from data in a neighbourhood of a mark and is based on an induced smoothed estimation equation, which is very different from the existing methods for competing risk data with discrete causes. The asymptotic properties of the resulting estimators are established across mark and quantile continuums. In addition, a mark-specific quantile-type vaccine efficacy is proposed and its statistical inference procedures are developed. Simulation studies are conducted to evaluate the finite sample performances of the proposed estimation and hypothesis testing procedures. An application to the first HIV vaccine efficacy trial is provided.

Analysing vaccine efficacy evaluated in phase 3 clinical trials carried out during outbreaks.

In this paper we examine several definitions of vaccine efficacy (VE) that we found in the literature, for diseases that express themselves in outbreaks, that is, when the force of infection grows in time, reaches a maximum and then vanishes. The fact that the disease occurs in outbreaks results in several problems that we analyse. We propose a mathematical model that allows the calculation of VE for several scenarios. Vaccine trials usually needs a large number of volunteers that must be enrolled. Ideally, all volunteers should be enrolled in approximately the same time, but this is generally impossible for logistic reasons and they are enrolled in a fashion that can be replaced by a continuous density function (for example, a Gaussian function). The outbreak can also be replaced by a continuous density function, and the use of these density functions simplifies the calculations. Assuming, for example Gaussian functions, one of the problems one can immediately notice is that the peak of the two curves do not occur at the same time. The model allows us to conclude: First, the calculated vaccine efficacy decreases when the force of infection increases; Second, the calculated vaccine efficacy decreases when the gap between the peak in the force of infection and the peak in the enrollment rate increases; Third, different trial protocols can be simulated with this model; different vaccine efficacy definitions can be calculated and in our simulations, all result are approximately the same. The final, and perhaps most important conclusion of our model, is that vaccine efficacy calculated during outbreaks must be carefully examined and the best way we can suggest to overcome this problem is to stratify the enrolled volunteer's in a cohort-by-cohort basis and do the survival analysis for each cohort, or apply the Cox proportional hazards model for each cohort.

The efficacy and safety of a quadrivalent live attenuated influenza nasal vaccine in Japanese children: A phase 3, randomized, placebo-controlled study.

BACKGROUND: Vaccination is the primary method of preventing influenza infection and complications in young children. We evaluated the efficacy and safety of a single dose of MEDI3250 (intranasal, quadrivalent, live attenuated influenza vaccine) in healthy Japanese children during the 2016/17 influenza season. METHODS: In this multicenter, randomized, double-blind, phase 3 study (jRCT2080223345), participants aged 2-18 years received MEDI3250 or placebo (2:1), stratified by age (2-6 years, 7-18 years). The primary and secondary endpoints were the incidence of confirmed symptomatic onset of influenza caused by a circulating wild-type strain or by a vaccine-matched strain, respectively. Safety outcomes included the incidence of adverse events (AEs) and vaccine-related AEs. RESULTS: Overall, 910 participants received MEDI3250 (n = 608) or placebo (n = 302). For the primary endpoint (regardless of the influenza subtype), the incidence of influenza onset was 25.5 % (MEDI3250) and 35.9 % (placebo); relative risk reduction, 28.8 % (95 % confidence interval, 12.5 %-42.0 %). For the secondary endpoint (vaccine-matched strain), the incidence was 10.9 % (MEDI3250) and 17.2 % (placebo); relative risk reduction, 36.6 % (95 % confidence interval, 6.5 %-56.8 %). Solicited AEs occurred in 67.6 % (MEDI3250) and 63.6 % (placebo). Most events were mild; nasal discharge was most common (59.2 % [MEDI3250] and 52.6 % [placebo]). Unsolicited AEs occurred in 36.0 % (MEDI3250) and 33.1 % (placebo). The most common unsolicited vaccine-related AE was diarrhea (2.3 %, both groups). CONCLUSIONS: MEDI3250 had a greater preventive effect against influenza onset in Japanese children than placebo; no new safety signals were observed relative to previous clinical and post-marketing studies of MEDI3250.

Chronological Management of Adjuvant Effect for Optimized mRNA Vaccine Inspired by Natural Virus Infection.

The efficacy and safety of mRNA vaccines both rely on a fine-tuning of specific humoral and cellular immune responses. Instead of adjustments in vaccine component, we proposed a concept of chronological management of adjuvant effect to modulate the adaptive immune potency and preference inspired by natural virus infection. By simulating type I interferon expression dynamics during viral infection, three vaccine strategies employing distinct exposure sequences of adjuvant and mRNA have been developed, namely Precede, Coincide, and Follow. Follow, the strategy of adjuvant administration following mRNA, effectively suppressed tumor progression, which was attributed to enhanced mRNA translation, augmented p-MHC I expression, and elevated CD8+ T cell response. Meanwhile, Follow exhibited improved biosafety, characterized by reduced incidences of cardiac and liver toxicity, owing to its alteration to the vaccination microenvironment between successive injections. Our strategy highlights the importance of fine-tuning adjuvant effect dynamics in optimizing mRNA vaccines for clinical application.

Case-cohort design as an efficient approach to evaluating COVID-19 vaccine effectiveness, waning, heterologous immune effect and optimal dosing interval.

Though widely applied in other epidemiological fields, the case-cohort study design has seen little application in the field of vaccinology. Case-cohort studies use probabilistic sampling and reweighting to draw inferences about effects (in this case vaccine efficacy) at the population level in an efficient manner. The SARS-CoV-2 pandemic was met with high vaccine uptake, and high rates of population testing prior to the emergence of Omicron variants of concern, in Ontario, Canada, providing an ideal environment for application of case-cohort methodology. We combined a population-based case line list and vaccination database for the province of Ontario between December 2020 and October 2021. Risk of infection after vaccination was evaluated in all laboratory-confirmed vaccinated SARS-CoV-2 cases, and a 2 % sample of vaccinated controls, evaluated using survival analytic methods, including construction of Cox proportional hazards models. Vaccination status was treated as a time-varying covariate. First and second doses of SARS-CoV-2 vaccine markedly reduced risk of infection (first dose efficacy 68 %, 95 % CI 67 %-69 %; second dose efficacy 88 %, 95 % CI 87-88 %). In multivariable models, extended dosing intervals were associated with lowest risk of breakthrough infection (HR for redosing 0.64 (95 % CI 0.61-0.67) at 6-8 weeks). Heterologous vaccine schedules that mixed viral vector vaccine first doses with mRNA second doses were significantly more effective than mRNA only vaccines. Risk of infection largely vanished during the time period 4-6 months after the second vaccine dose, but rose markedly thereafter. We conclude that a case-cohort design provided an efficient means to identify strong protective effects associated with SARS-CoV-2 vaccination in real time, and also served to quantify the timing and magnitude of infection breakthrough risk in the same cohort. Heterologous vaccination and extended dosing intervals improved the durability of immune response.

Assessing the Impact of COVID-19 Vaccination Programs on the Reduction of COVID-19 Cases: A Systematic Literature Review.

Background: Vaccination is the most effective way to prevent serious illness and death from COVID-19 among the various preventive interventions available. Objective: This review aimed to assess the actual effectiveness of COVID-19 vaccines in curbing the transmission and incidence of COVID-19 cases, to examine the role of different vaccine types in controlling the COVID-19 pandemic, as well as to identify the key factors influencing the efficacy of COVID-19 vaccines in containing the spread of the virus. Methods: The suggestions made by the PRISMA Framework were adhered to. To find the publications for the 2020-2023 timeframe, searches were performed through the PubMed databases, EMBASE, Scopus, and ProQuest. For the review, 17 reports satisfied the inclusion requirements. Ad26.CoV2.S or ChAdOx1-S, Gam-COVID-Vac(GAM), Sinovac Life Sciences Co., Oxford-AstraZeneca, Pfizer-BioNTech, and viral vector vaccines are among the vaccines that act on various variations. They dealt with the Delta, B.1.1.519, Omicron, and Alpha variations. Findings: Vaccinations against various Variants resulted in fewer COVID-19 infections, fewer deaths, and fewer hospitalizations. The emergency of the Delta variant, persons over 60, and vaccine hesitancy were the main issues affecting the effectiveness of COVID-19 vaccinations in containing the virus's spread. Conclusion: The collective evidence strongly supports the conclusion that COVID-19 vaccination plays a crucial role in mitigating the spread of the virus and reducing the severity of illness among those who contract the virus.

Social Media Authentication and Users' Assessments of Health Information: Random Assignment Survey Experiment.

BACKGROUND: In an effort to signal the authenticity of user accounts, social networking sites (SNSs) such as Facebook and X, formerly known as Twitter, use visual heuristics (blue checkmarks) to signify whether accounts are verified. While these verification badges are generally well recognized (and often coveted) by SNS users, relatively little is known about how they affect users' perceptions of accuracy or their likelihood of engaging with web-based information. This is particularly true in the case of information posted by medical experts and health care professionals. OBJECTIVE: This study aims to use an experimental survey design to assess the effect of these verification badges on SNS users' assessments of information accuracy as well as their proclivity to recirculate health information or follow verified medical experts in their social network. METHODS: A survey experiment using random assignment was conducted on a representative sample of 534 adult SNS users in Florida, United States. A total of 2 separate experimental scenarios exposed users to vaccine-related posts from verified medical experts on X. In each case, the original post contained a platform-issued verification badge (treatment group), which was subsequently edited out of the image as an experimental control. For each scenario, respondents were randomly assigned to either the treatment or control group, and responses to 3 follow-up questions were assessed through a series of chi-square analyses and 2 logit regression models. Responses were fielded using a stratified quota sampling approach to ensure representativeness of the state's population based on age, sex, race, ethnicity, and political affiliation. RESULTS: Users' assessments of information accuracy were not significantly impacted by the presence or absence of verification badges, and users exposed to the experimental treatment (verification badge) were not any more likely to repost the message or follow the author. While verification badges did not influence users' assessments or subsequent behaviors, reliance on social media for health-related information and political affiliation were substantial predictors of accuracy assessments in both experimental scenarios. In scenario 1, which included a post addressing COVID-19 vaccine efficacy, users who relied on social media "a great deal" for health information were 2 times more likely to assess the post as accurate (odds ratio 2.033, 95% CI 1.129-3.661; P=.01). In scenario 2, which included a post about measles vaccines, registered Republicans were nearly 6 times less likely to assess the post as accurate (odds ratio 0.171, 95% CI 0.097-0.299; P<.001). CONCLUSIONS: For health professionals and medical experts wishing to leverage social networks to combat misinformation and spread reliable health-related content, account verification appears to offer little by way of added value. On the basis of prior research, other heuristics and communication strategies are likely to yield better results.

Different Neutralizing Antibody Responses of Heterologous Sera on Sheeppox and Lumpy Skin Disease Viruses.

Sheeppox virus (SPPV), goatpox virus (GTPV), and lumpy skin disease virus (LSDV) are the three members of the genus Capripoxvirus within the Poxviridae family and are the etiologic agents of sheeppox (SPP), goatpox (GTP), and lumpy skin disease (LSD), respectively. LSD, GTP, and SPP are endemic in Africa and Asia, causing severe disease outbreaks with significant economic losses in livestock. Incursions of SPP and LSD have occurred in Europe. Vaccination with live attenuated homologous and heterologous viruses are routinely implemented to control these diseases. Using the gold standard virus neutralization test, we studied the ability of homologous and heterologous sera to neutralize the SPPV and LSDV. We found that LSD and SPP sera effectively neutralize their homologous viruses, and GTP sera can neutralize SPPV. However, while LSD sera effectively neutralizes SPPV, SPP and GTP sera cannot neutralize the LSDV to the same extent. We discuss the implications of these observations in disease assay methodology and heterologous vaccine efficacy.

Multivalent mRNA Vaccine Elicits Broad Protection against SARS-CoV-2 Variants of Concern.

SARS-CoV-2 new waves are primarily caused by changes to the spike protein (S), which can substantially decrease the efficacy of vaccines. Therefore, we tested several multivalent mRNA-LNP vaccines, targeting the full-length S proteins of different variants, and identified an optimal combination for protection against VOCs in BALB/c mice. The tested formulations included trivalent (WT + BA.5 + XBB.1.5), pentavalent (WT + BA.5 + XBB.1.5 + BQ.1.1 + CH.1.1), and octavalent (WT + BA.5 + XBB.1.5 + BQ.1.1 + CH.1.1 + Alpha + Delta + BA.2) vaccines. Among these multivalent vaccines, the pentavalent vaccine showed superior protection for almost all tested variants. Despite this, each multivalent vaccine elicited greater broad-spectrum neutralizing antibodies than the previously evaluated bivalent vaccine (WT + BA.5). Subsequently, we redesigned the multivalent vaccine to efficiently generate neutralizing antibodies against recent VOCs, including EG.5.1. Immunization with the redesigned pentavalent vaccine (WT + EG.5.1 + XBB.1.16 + Delta + BA.5) showed moderate levels of protection against recent Omicron VOCs. Results suggest that the neutralization activity of multivalent vaccines is better than those of the tested bivalent vaccines against WT + BA.5 and WT + EG.5.1. Moreover, the pentavalent vaccine we developed may be highly useful for neutralizing new Omicron VOCs.

Trichinella spiralis Infection Inhibits the Efficacy of RBD Protein of SARS-CoV-2 Vaccination via Regulating Humoral and Cellular Immunity.

Vaccines are the most effective and feasible way to control pathogen infection. Helminths have been reported to jeopardize the protective immunity mounted by several vaccines. However, there are no experimental data about the effect of helminth infection on the effectiveness of COVID-19 vaccines. Here, a mouse model of trichinosis, a common zoonotic disease worldwide, was used to investigate effects of Trichinella spiralis infection on the RBD protein vaccine of SARS-CoV-2 and the related immunological mechanism, as well as the impact of albendazole (ALB) deworming on the inhibitory effect of the parasite on the vaccination. The results indicated that both the enteric and muscular stages of T. spiralis infection inhibited the vaccine efficacy, evidenced by decreased levels of IgG, IgM, sIgA, and reduced serum neutralizing antibodies, along with suppressed splenic germinal center (GC) B cells in the vaccinated mice. Pre-exposure to trichinosis promoted Th2 and/or Treg immune responses in the immunized mice. Furthermore, ALB treatment could partially reverse the inhibitory effect of T. spiralis infection on the efficiency of the vaccination, accompanied by a restored proportion of splenic GC B cells. Therefore, given the widespread prevalence of helminth infections worldwide, deworming therapy needs to be considered when implementing COVID-19 vaccination strategies.

Evaluating Factors That Influence Influenza Vaccination Uptake among Pregnant People in a Medically Underserved Area in Washington State.

INTRODUCTION: Despite substantial evidence demonstrating the effectiveness of influenza vaccines, only 38.6% of the adult United States population received an influenza vaccine during the 2023-2024 flu season. Vaccination rates are typically lower among U.S. minority groups, and in 2022, pregnant persons from U.S. minority racial and ethnic groups showed a decrease in influenza vaccine coverage. METHODS: A survey was conducted with residents of Yakima County, Washington, which is home to one of the state's largest percentages of people who identify as Hispanic or Latino/a. The objective was to evaluate the uptake of influenza vaccine among pregnant persons. Surveys were sent to a random sample of 3000 residential mailing addresses. Of the 500 respondents, 244 (52.1%) reported that they had been pregnant, with those identifying as Hispanic or Latino/a constituting 23.8% of this total. Only 62 (26.2%) reported being immunized against influenza during pregnancy. Respondents who were immunized against influenza chose to be vaccinated to protect themselves from the flu (85.5%, n = 53); because a healthcare provider recommended getting vaccinated (85.5%, n = 53); to protect the baby from the flu (82.3%, n = 51); because it was available for free or low cost (62.9%, n = 39); and because vaccination was convenient (54.8%, n = 34). Qualitative evaluation identified that participants who were not vaccinated against influenza during pregnancy believed the vaccination was not needed, was not recommended by a healthcare provider, was difficult to access, they were against vaccination in general, or they were concerned about the safety and ingredients of the vaccine. CONCLUSION: Barriers to vaccination identified in this study included vaccine distrust, lack of awareness, and concerns about vaccine efficacy and safety. Healthcare providers can help address these concerns by providing education and recommendations about the importance of influenza vaccination during pregnancy.

Immunogenicity, Safety and Efficacy of the Dengue Vaccine TAK-003: A Meta-Analysis.

The TAK-003 dengue vaccine was licensed in Europe in December 2022, and the official recommendations from most EU countries are still under formulation. To support policymakers, we performed a meta-analysis to quantify TAK-003's immunogenicity, efficacy and safety among seronegative and seropositive populations after the administration of one or two vaccine doses. We included trials retrieved from MEDLINE, Scopus and ClinicalTrials.gov. The outcomes were the rates of seroconversion, virologically confirmed dengue fever and serious adverse events after each vaccine dose. Data were combined using random-effect proportion or head-to-head meta-analyses. We retrieved a total of 19 datasets, including >20,000 participants. TAK-003 showed an excellent safety profile, and the immunogenicity after two doses against the four DENV serotypes was ≥90% among both adults and children/adolescents who were either seronegative or seropositive at baseline. A single dose was able to elicit a high immunogenic response among adults (≥70%) and children/adolescents (≥90%). The primary two-dose immunization course halved the risk of all types of virologically confirmed dengue fever among seropositive children/adolescents, but seronegative minors were only protected against the diseases caused by DENV-1 and DENV-2. Overall, the results support the use of TAK-003 for the prevention of dengue fever in the pediatric population of endemic countries. Uncertainties remain on the use of a single vaccine dose in non-endemic countries.

Efficacy of Recombinant Marek's Disease Virus Vaccine 301B/1 Expressing Membrane-Anchored Chicken Interleukin-15.

Cytokines are co-administrated with vaccines or co-expressed in the vaccine virus genome to improve protective efficacy by stimulating immune responses. Using glycosylphosphatidylinositol (GPI) anchoring by attachment to the target cytokine, we constructed recombinant Marek's disease virus (MDV) vaccine strain 301B/1 (v301B/1-rtg-IL-15) that expresses chicken interleukin-15 (IL-15) as the membrane-bound form at the cell surface. We evaluated the vaccine efficacy of v301B/1-rtg-IL-15 given as a bivalent Marek's disease (MD) vaccine in combination with turkey herpesvirus (HVT) against a very virulent plus MDV strain 648A challenge. The efficacy was compared with that of conventional bivalent MD vaccine, as a mixture with HVT plus parental v301B/1 or v301B/1-IL-15, which expresses a natural form of IL-15. The membrane-bound IL-15 expression did not interfere with the virus growth of recombinant v301B/1-rtg-IL-15. However, the MD incidence in birds vaccinated with v301B/1-rtg-IL-15 was higher than that of birds given the conventional bivalent MD vaccine containing parental v301B/1 virus, although the v301B/1-rtg-IL-15 vaccinated group showed increased natural killer cell activation at day 5 postvaccination, the same day as challenge. Overall, the protection of v301B/1-rtg-IL-15 was not improved from that of v301B/1 against very virulent plus MDV challenge.

Eficacia de una vacuna contra el virus de la enfermedad de Marek cepa 301B/1 recombinante que expresa la interleucina-15 de pollo anclada a la membrana. Las citocinas se administran junto con vacunas o se co-expresan en el genoma del virus de la vacuna para mejorar la eficacia protectora mediante la estimulación de respuestas inmunitarias. Utilizando el anclaje de glicosilfosfatidilinositol (GPI) mediante unión a la citoquina objetivo, se construyó una cepa de vacuna recombinante del virus de la enfermedad de Marek (MDV) 301B/1 (v301B/1-rtg-IL-15) que expresa la interleucina-15 de pollo (IL-15) como la forma unida a la membrana en la superficie celular. Se evaluó la eficacia de la vacuna v301B/1-rtg-IL-15 administrada como vacuna bivalente en combinación con el herpesvirus del pavo (HVT) contra el desafío con un virus muy virulento cepa 648A de la enfermedad de Marek (MD). La eficacia se comparó con la de la vacuna bivalente convencional contra la enfermedad de Marek, como una mezcla con HVT más la cepa v301B/1 parental o con el virus recombinante v301B/1-IL-15, que expresa una forma natural de IL-15. La expresión de IL-15 unida a membrana no interfirió con el crecimiento del virus de v301B/1-rtg-IL-15 recombinante. Sin embargo, la incidencia de la enfermedad de Marek en aves vacunadas con v301B/1-rtg-IL-15 fue mayor que la de las aves que recibieron la vacuna de Marek bivalente convencional que contenía el virus v301B/1 parental, aunque el grupo vacunado con v301B/1-rtg-IL-15 mostró una mayor activación de las células asesinas naturales en el día 5 después de la vacunación, que fue el mismo día del desafío. En general, la protección por la vacuna v301B/1-rtg-IL-15 no mejoró con respecto a la conferida por v301B/1 contra un desafío muy virulento de la enfermedad de Marek.

Heterologous versus homologous COVID-19 booster vaccinations for adults: systematic review with meta-analysis and trial sequential analysis of randomised clinical trials.

BACKGROUND: To combat coronavirus disease 2019 (COVID-19), booster vaccination strategies are important. However, the optimal administration of booster vaccine platforms remains unclear. Herein, we aimed to assess the benefits and harms of three or four heterologous versus homologous booster regimens. METHODS: From November 3 2022 to December 21, 2023, we searched five databases for randomised clinical trials (RCT). Reviewers screened, extracted data, and assessed bias risks independently with the Cochrane risk-of-bias 2 tool. We conducted meta-analyses and trial sequential analyses (TSA) on our primary (all-cause mortality; laboratory confirmed symptomatic and severe COVID-19; serious adverse events [SAE]) and secondary outcomes (quality of life [QoL]; adverse events [AE] considered non-serious). We assessed the evidence with the GRADE approach. Subgroup analyses were stratified for trials before and after 2023, three or four boosters, immunocompromised status, follow-up, risk of bias, heterologous booster vaccine platforms, and valency of booster. RESULTS: We included 29 RCTs with 43 comparisons (12,538 participants). Heterologous booster regimens may not reduce the relative risk (RR) of all-cause mortality (11 trials; RR 0.86; 95% CI 0.33 to 2.26; I2 0%; very low certainty evidence); laboratory-confirmed symptomatic COVID-19 (14 trials; RR 0.95; 95% CI 0.72 to 1.25; I2 0%; very low certainty); or severe COVID-19 (10 trials; RR 0.51; 95% CI 0.20 to 1.33; I2 0%; very low certainty). For safety outcomes, heterologous booster regimens may have no effect on SAE (27 trials; RR 1.15; 95% CI 0.68 to 1.95; I2 0%; very low certainty) but may raise AE considered non-serious (20 trials; RR 1.19; 95% CI 1.08 to 1.32; I2 64.4%; very low certainty). No data on QoL was available. Our TSAs showed that the cumulative Z curves did not reach futility for any outcome. CONCLUSIONS: With our current sample sizes, we were not able to infer differences of effects for any outcomes, but heterologous booster regimens seem to cause more non-serious AE. Furthermore, more robust data are instrumental to update this review.

Feasibility of Using a Type I IFN-Based Non-Animal Approach to Predict Vaccine Efficacy and Safety Profiles.

Animal-based tests are used for the control of vaccine quality. However, because highly purified and safe vaccines are now available, alternative approaches that can replace or reduce animal use for the assessment of vaccine outcomes must be established. In vitro tests for vaccine quality control exist and have already been implemented. However, these tests are specifically designed for some next-generation vaccines, and this makes them not readily available for testing other vaccines. Therefore, universal non-animal tests are still needed. Specific signatures of the innate immune response could represent a promising approach to predict the outcome of vaccines by non-animal methods. Type I interferons (IFNs) have multiple immunomodulatory activities, which are exerted through effectors called interferon stimulated genes (ISGs), and are one of the most important immune signatures that might provide potential candidate molecular biomarkers for this purpose. This paper will mainly examine if this idea might be feasible by analyzing all relevant published studies that have provided type I IFN-related biomarkers for evaluating the safety and efficacy profiles of vaccines using an advanced transcriptomic approach as an alternative to the animal methods. Results revealed that such an approach could potentially provide biomarkers predictive of vaccine outcomes after addressing some limitations.

SARS-CoV-2 vaccination in inflammatory bowel disease (IBD) patients - does treatment for IBD negatively affect SARS-CoV-2 antibodies? A single-centre, prospective study.

Introduction: Inflammatory bowel disease (IBD) patients use a wide variety of immunosuppressive drugs, including biologics, but their effect on SARS-CoV-2 vaccine antibody levels remains a mystery. Aim: We analysed whether the drugs used in the treatment of IBD patients could affect the concentration of SARS-CoV-2 antibodies. Material and methods: This is a prospective, single-centre evaluation of the persistence of SARS-CoV-2 antibodies after vaccination at various time points: every 2 months throughout the 6th month after the first dose. Results: We included a total of 346 vaccinated IBD patients in the study. A negative correlation between antibody level and time from full vaccination was confirmed for the following types of therapy: infliximab (rho = -0.32, p < 0.001), adalimumab (rho = -0.35, p = 0.025), and vedolizumab (rho = -0.50, p < 0.001). In the case of other, long-term drug administration, a negative correlation between antibody level and time from full vaccination was confirmed for mesalazine (rho = -0.35, p < 0.001), budesonide (rho = -0.58, p = 0.004), systemic glucocorticoids (rho = -0.58, p < 0.001), and azathioprine (rho = -0.44, p < 0.001). Conclusions: Due to the immunosuppressive and biological treatment, IBD patients are exposed to a shorter persistence of SARS-CoV-2 antibodies and require booster doses. The role of gastroenterologists in educating patients about the need to continue SARS-CoV-2 vaccination remains crucial.

Mapping and ranking outcomes for the evaluation of seasonal influenza vaccine efficacy and effectiveness: a delphi study.

BACKGROUND: Protection provided by seasonal influenza vaccination (SIV) may be measured against numerous outcomes, and their heterogeneity may hamper decision-making. The aim of this study was to explore outcomes used for estimation of SIV efficacy/effectiveness (VE) and obtain expert consensus on their importance. RESEARCH DESIGN AND METHODS: An umbrella review was first conducted to collect and map outcomes considered in systematic reviews of SIV VE. A Delphi study was then performed to reach expert convergence on the importance of single outcomes, measured on a 9-point Likert scale, in principal target groups, namely children, working-age adults, older adults, subjects with co-morbidities and pregnant women. RESULTS: The literature review identified 489 outcomes. Following data reduction, 20 outcomes were selected for the Delphi process. After two Delphi rounds and a final consensus meeting, convergence was reached. All 20 outcomes were judged to be important or critically important. More severe outcomes, such as influenza-related hospital encounters and mortality with or without laboratory confirmation, were generally top-ranked across all target groups (median scores ≥8 out of 9). CONCLUSIONS: Rather than focusing on laboratory-confirmed infection per se, experimental and observational VE studies should include more severe influenza-related outcomes because they are expected to exercise a greater impact on decision-making.

Vaccine Effectiveness against SARS-CoV-2 among Household Contacts during Omicron BA.2-Dominant Period, Japan.

We calculated attack rates for household contacts of COVID-19 patients during the SARS-CoV-2 Omicron BA.2-dominant period in Japan. Attack rates among household contacts without recent (<3 months) vaccination was lower for contacts of index patients with complete vaccination than for contacts of index patients without complete vaccination, demonstrating indirect vaccine effectiveness.